Induction-coil



(No Model.)

B. THOMSON. INDUCTION COIL.

Patented Aug. 27, 1889.

I w mu m M ATTORNEYS N PETERS. PhcIa-Lflhogmphr, Washington. DC,

UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE THOMSON- I IOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

INDUCTION-COIL.

SPECIFICATION forming part of Letters Patent No. 409,714, dated August 27, 1889.

Application filed February 12, 1887. Serial No. 227,445. (No model.)

To all whom it may concern: pieces of the same form. After the coils arein Be it known that I, ELIHU THOMSON, a citiplace there should be sufficient iron projectzen of the United States, and a resident of ing beyond them to permit the introduction Lynn, in the county of Essex and State of of bundles of sheet-iron pieces I, adaptedto 55 Massachusetts, have invented a certain new fit closely in the space between the projecand useful In duction-Coil, of which the followtions and to make a butt-j oint, with their edges ing is a specification. against the internal edges of the legs of the My invention relates to those forms of elecpieces I I at the part thereof lying beyond tro-magnets in which a coil or coils are wound or to the opposite of the coilsP S. The mag- 60 upon a subdivided iron core made up of sepanetic sections of the bundles I I should be rate plates or laminae. approximately equal to the magnetic section My inventionis designed more particularly of the four pieces I I It will be seen that as animprovementin the construction of those by this construction of iron core and magforms of magnetwhich are provided with two netic circuit-closing bundle I no spaces 65 coils, one of'which bears the relation to the are required to be left between individual other of a primary coil of a converter or inspaces 1 to form gaps for the insertion duction coil. of plates or pieces of the bundle I, and that The object of my invention is to secure therefore the greatest practicable mass of cheapness and ease of construction together iron consistent with a proper magnetic sub- 70 with high efficiency of action, due to the pardivision may be obtained in a given space. ticular proportion of coils and core herein- \Vhcn the coils P S, &c., occupy a square after described, and to the fact that the iron figure in combined section, Fig. 1, the best mass is as nearly as possible solid. proportioning demands that the outer lines In the accompanying drawings, Figure 1 is of I I and of I I be also square2'. e., 7 5 avertical section of an apparatus embodying the pieces I I should be punched out square my invention, and Fig. 2 is a side elevation except Where the slots for the coils P S and of the same. Figs. 3 and 4 are respectively for I exist. It is also preferred to economize vertical U-sections and a side elevation of a the material (copper) of the coils P and S by modification. Figs. 5 and 6 show my invenusing a large proportion of iron. If the coils 8o 0 tion in another modified form. Fig. 7 shows P and S occupy a square figure of two inches another form of U-shaped plate adapted to on the side, the pieces I 1 including 1, may my invention. Figs. 1 and 2 show the prebe of a square of six inches on the other side, ferred construction. or the total external dimensions of the parts,

Sheet-iron punched into U-shaped pieces Fig. 1, will be rectangular six inches from a 3 5 of preferably square form (seen at I and 1 to b and c to (Z and twelve inches from a to c Fig. 1) are used to build up a core. (Seen and Z) to (1, while the iron all around the coils on edge, Fig. 2,11 In the notches are wound P S will represent a layer two inches thick. the two coils P and S, as indicated, and to- As will be observed, each leg of the U-shaped get-her they form approximatelya square secplate projects beyond the body of the coil to 40 tion, the four sides of which are of square .a distance substantially equal to the width of length. each leg. A larger proportion of sheet-iron The winding may be accomplished readily would require larger outside dimensions and by revolving the parts of the core I 1 held in would involve the use of a layer of iron of suitable clamps, and feeding the wire of the greater depth around the coil and through its 5 coilsthereon,asusual. The coils passthrough center. Thus with the section of coils P S the grooves orbetween the legs of the U-pieces occupying a square figure of two inches as and over the ends, as seen in Fig. 2, and of before, and with a diameter from c to f of six course are insulated thoroughlyfrom theiron inches, the iron layer may be made three pieces I I by interposed layers of insulating inches thick, which would make the dimen- I00 50 material. The sheet-iron pieces themselves sions from a to b eight inches and from a to may be insulated by interposed thin paper 0 sixteen inches.

By the particular proportions of coils and magnetic masses hereinbefore described I obtain the maximum efiiciency with the mini mum amount of material and space required for the coil. A thin layer of materialsuch as hard paper or other insulationmay be interposed, if desired, between the edges of I and I, but should not be sufiiciently thick to interfere greatly with the magnetic continuity.

Figs. 3 and 4 show a modification in which the core I is short and composed of sheet-iron or wires dressed off at the ends to fit into a frame I after the coils P and S have been placed upon the core I The frame I is composed of sheet-iron pieces of double-U form, the legs of the two U s being joined integral. The plates are laid together laterally and serve to eifect external closure of the magnetic circuit of the core I.

The material which is used to separate the various plates I, I and I from one another may consist of paper interposed between the flat surfaces of such plates.

Figs. 5 and 6 show a modification, in which the pieces I I are set radially and fitted together by tapering their inner edges, or by making them of varying dimensions, so as to nearly fill the centerof the coils. Externally they (I I are joined,as before,bybundles of sheet-iron strips properly insulated. The construction gives a circular form to the whole, but has no special advantage overthe form shown in Figs. 1 and 2 for practical purposes.

It is obvious that plates of the double-U form shown in Fig. 7 might take the place of the plates I 1 Figs. 1 and 2.

The special form shown in Figs. 3 and 4 of the accompanying drawings forms the subject of specific claims in an application filed by me September 29, 1887, Serial No. 251,072, and constituting a division of the present application.

I do not claim herein the combination, with the coils, of U shaped iron plates or pieces, between whose legs the conductor and coil lie, and yoke-pieces connecting the two legs, so as to complete a magnetic circuit around the circumferential axis of the coil; nor do I claim herein the combination, with one or more electric coils, of a magnetic envelope formed at the sides of the coil, of two masses of iron subdivided in lines transverse to the line of the coils, but substantially parallel to the plane of winding, and yoke-pieces connecting the iron at the sides of the coil on the outer periphery thereof, as these features form the subject of claims in another application for patent filed of even date herewith,- Serial No. 227,446.

What I claim as my invention is- 1. The combination, with an electric coil, of a bundle of U-shaped iron plates or pieces, between whose legs the conductors of the coil lie, in combination with yoke-pieces consisting of bundles of iron plates fitted into the space between the projecting ends of the legs of the U and forming a butt-joint with theinternal edges of said legs, so as to complete a solid magnetic circuit around the circumferential axis of the coil.

2. The combination, with an electric coil, of

an enveloping iron mass consisting of a bundle of iron plates passing through the axis of the coil and around the outside thereof, together with a bundle of sheet-iron plates insulated from one another and fitting into the space between the extensions of the first-named iron mass and forming a buttejoint with the edges of the plates making up such mass, as and for the purpose described.

3. The combination, in an induction-coil or converter, of primary and secondary coils whose combined cross-section is a square figure having four sides of equal length, in combination with a series of superposed U shaped plates passing through said coil, and having legs which project beyond the coils to a distance substantially equal to the thickness of such coil, and a magnetic circuit-closing bundle of iron plates placed between the legs and having awidth equal to the width of the legs.

Signed at Lynn, in the county of Essex and State of Massachusetts, this 7th day of February, A. D. 1887.

ELII-IU THOMSON.

Witnesses:

J. W. GIBBONEY, E. WILBUR RICE, Jr. 

